Perhaps you should try some spelling variations:
doi chieu » doc hieu, doi chi, mot chieu
trang cua » tang cua, trung cua, thang cua
tranh cua » doanh cua, manh cua
thong tac » thong cac, tuong tac, thong tai
ho chieu » theo chieu, hoc thieu, mot chieu
tac toan » tap toan, tam toan, hach toan
toan cau » toan cao, toan ban, toan tap

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: ((ho chieu) or (doi chieu)) xanh - hanh ((trang cua) OR (tranh cua)) thong thong tac toan cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((ho chieu) OR (doi chieu)) xanh - hanh ((trang cua) OR (tranh cua)) thong thong tac toan cau.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((ho chieu) or (doi chieu)) xanh - hanh ((trang cua) OR (tranh cua)) thong thong tac toan cau".
• Adding a wildcard symbol may retrieve word variants: ((ho chieu) or (doi chieu)) xanh - hanh ((trang cua) OR (tranh cua)) thong thong tac toan cau*.